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TROUBLESHOOTING WORKSHOP

SWR too high?

Separate measurement setup, cable and antenna before changing antenna length.

Switch the transmitter off before working on the RF path. Never connect a VNA to a transmitting output. Consult each device’s manual for permitted power and SWR limits.

YOUR NEXT USEFUL TEST

Check the antenna path section by section

The reference is plausible, but the connected system remains suspect. This narrows the area without identifying a particular faulty part.

  1. With the transmitter off, substitute additional adapters, switches and cable sections individually with known suitable components. Remeasure after each change.
  2. Where possible compare the antenna directly at its feed point using a disconnected analyser. Record the measurement plane: a lossy cable can make SWR appear better at the station end.

What to look for next

Associate a repeatable change with one section. Assess cable loss and matching together.

Related learning & practice

Technical sources for this check

Background and model-specific guidance; the check sequence is editorial. Match menu names against your own model’s manual.

Show check record
HB3YAQ · Check record: SWR too high?
Your answers; no automatic measurement.

1. Do cable, connectors and antenna connection look sound?
→ Yes, nothing visibly wrong
2. How are you measuring SWR?
→ With a VNA or antenna analyser
3. Is reflection measurement calibrated for this setup?
→ Yes, at the intended measurement plane
4. What does a suitable known matched load show?
→ Near 1:1, within measurement accuracy
5. How does SWR vary with frequency?
→ Unexpectedly high throughout the range

Check the antenna path section by section
The reference is plausible, but the connected system remains suspect. This narrows the area without identifying a particular faulty part.
1. With the transmitter off, substitute additional adapters, switches and cable sections individually with known suitable components. Remeasure after each change.
2. Where possible compare the antenna directly at its feed point using a disconnected analyser. Record the measurement plane: a lossy cable can make SWR appear better at the station end.
Associate a repeatable change with one section. Assess cable loss and matching together.

ARRL · Feed lines: https://www.arrl.org/feed-lines
ARRL / Darrin Walraven · Understanding SWR by Example: https://www.arrl.org/files/file/Technology/tis/info/pdf/q1106037.pdf

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